For the last month, I have driven the future. I tootled around town in a pea-green Toyota Prius, a hybrid electric Toyota, the first of its kind to make an appearance in the United States.

You can't buy it yet, because it won't hit the U.S. market until July. When it does, get the metaphors ready. This is going to be a barnburner, a torrid affair, a car to change habits and attitudes in a lasting way.

Prius (pronounced PREE-us) is run by a 40-horsepower electric motor or a 58-horsepower, four-cylinder gasoline engine, or a combination of the two. The battery-powered electric motor runs the car at its lowest speeds. The 1.5-liter gas engine takes over only when it can run most efficiently (usually at about 25 mph and above). The car shifts between the two automatically and seamlessly. Toyota says it should give 55 mpg, nearly five times what your basic gas-inhaling SUV gets.

Unlike all-electric cars, the batteries aboard the Prius do not need to be plugged in for charging. The gasoline motor charges them as the car is driven, and each time you step on the brake, you generate power and send it back to the batteries automatically. According to the manufacturer, the battery pack has an expected life of 150,000 miles, as much as the car itself.

The result is an environmentalist's dream. The Prius emits approximately one-fifth the pollutants of a standard gas-powered sedan. If most of your trips are 10 miles or less, Prius makes sense.

Our family was one of five in the Washington-Baltimore area chosen by Toyota to test-drive a Prius for a month. We were told to use it as we would the cars we already own. After half a day of training, we were handed the keys and sent on our way.

A month later, my scorecard is full of smiles.

We spent exactly $8.40 on gas (six gallons) to travel just under 250 miles. That's a little more than 40 miles a gallon. We would have gotten better gas mileage, I'm sure, if the weather had been warmer and if I had driven with a lighter foot.

We drove in heavy rain and serious wind without a hint of a slide or a sway. We parked where cars even a foot longer never could have fit.

We wowed 'em in shopping center parking lots and at soccer practice. My wife fit four sweaty seventh-grade basketball players, their backpacks, their gym bags and herself into the car one day without the slightest strain. We had total strangers march up to us, listen to a 30-second explanation of what a Prius is, and offer to buy it on the spot.

We may even have helped resolve Toyota's knottiest question: Where's the American market for such an unsexy, unsleek, unlarge, unprepossessing vehicle?

On a freezing day in mid-January, I showed the car at my daughter's 12th-grade environmental science class in the school parking lot. I asked how many of the assembled 17- and 18-year-olds would buy it. Every hand shot up. I don't think it was just to get frozen blood flowing again.

Toyota plans to provide 12,000 Priuses to U.S. dealerships in July. Head-on competition won't arrive until model year 2003, when Ford is expected to introduce a hybrid electric model. Honda now sells an all-electric car, but it needs to be plugged into a recharger and has limited range.

Toyota has sold 30,000 Priuses in Japan since they went on the market there in 1997. That's considered good for a breakthrough car in that traditional country. Prius sold three months' worth of inventory in Japan on the first day it was offered.

America, however, is the land of the free and the home of the image. Cars always have sold best here if they have a swagger, a leave 'em in the dust attitude. Besides, Americans are used to getting as much car as possible if they spend between $20,000 and $22,000 (which is where Toyota expects to peg the Prius).

Will Yanks bend in the name of fuel economy and kindness to ferns? One woman I know who has three sons under age 13 was more concerned about space: Gail Thames walked up to the Prius, eyed it suspiciously and said, "Tell them to make a van."

The reaction of the passerby public was more favorable. I had 14 conversations at red lights during my Prius month. All began with a window rolled down and a curious person (almost always male) leaning out to ask, "What is it?"

Francisco, an attendant at a downtown parking lot, retrieved the Prius one day with a huge smile on his face. I asked what he thought. "I turn the key and it go wooo-o-o-o-o-o!," he said, admiringly.

In fact, one of the great appeals of Prius is that it often doesn't go wooo-o-o-o-o-o.

When you start the car, you are starting the batteries. So you hear nothing. It's like starting a flashlight. You don't step on the accelerator, so you don't hear the familiar throaty roar of the gas engine until it takes over--often as long as 15 seconds after you've started down the road.

The reverse happens, too, and it takes some getting used to. One day, with a Prius-ignorant passenger aboard, I stopped at a red light. The car kicked down from gas engine to batteries, and all noise ceased. "Hey, the car just died," said my passenger. "Not at all," I said, with a Cheshire Cat grin on my face.

The car's design also can be a bit jarring. The prototype that we drove was designed for the Japanese market, so some features may be subtracted or modified before U.S. sales begin. Still, have you ever driven a car whose odometer, speedometer and gas gauge are set far forward, under the lower lip of the windshield--and are in the center of the console? Meanwhile, the gearshift is strictly 1955 Citroen--a lever mounted on the dashboard that flips toward you as you shift, not straight down, as with most automatics.

About one-third of the dashboard is consumed by an electronic display. It shows, via orange and green arrows, which power source is being used to move the car. Otherwise, Prius has most of the comforts of cars in its price range--twin cup holders, a CD player, remote-control side mirrors, a defroster that would melt an iceberg.

The name Prius will not roll off anyone's tongue, and most of our test class didn't like it at all. It's a Latin word that means "to go before." The intention is to celebrate and reflect Prius's pioneering design. But at least half the passersby who discussed the car with me called it PRY-us, some even after I corrected them. No one ever mispronounces "Taurus," "Excursion" or "Grand Cherokee."

Toyota is facing an unusually interesting marketing challenge with Prius, especially in the Washington area, where Toyotas already sell very well.

Will interest in the Prius come at the expense of Echo, Corolla and Camry? Will budget-conscious Washingtonians pay $5,000 more for a Prius than for an Echo, which is almost the same size and gets about two-thirds of Prius's gas mileage? Will families want Prius as a second or third car, even though its low weight and sharply sloping snout make it a questionable bet for safe freeway driving? Should the car be marketed instead to Ma and Pa Kettle as an after-retirement, no-more-kids-to-schlep vehicle?

My guess is that it will appeal to the counter-car culture in the same way that Volkswagen's Bug did in the 1960s.

Prius will be the anti-SUV. Because it scoots and doesn't snarl, because it sips gas and doesn't chug it, it might do very well with the wool-shirt, hike-in-Vermont, NPR crowd. It will say, "If a Cadillac is a stodgy Republican car, and a Saab is a hip Democratic car, a Prius is a defiant Green Party car."

Advertising will tell the tale, as it often does in the U.S. car market. Our Prius tryout group was asked to invent an ad campaign. I told our final focus group meeting that I could easily imagine this 30-second TV spot:

A Prius trundles along an empty mountain road. The voice-over says: "Prius. Fifty-five miles to the gallon. One-fifth the pollution of other cars. No need to recharge the battery. Kind to your family and your world."

Then the Prius would veer softly off the road, pull up to a tree, stop, "stand" on its rear wheels and hug a tree with its front wheels. Nothing about speed or sex. Lots about social responsibility.

Yet the issue of safety lurks, and it may blot out Prius's sun. SUV buyers may think they're buying space and style. Many of them, at least subconsciously, are buying heft. If they have an accident, they want to be driving the biggest, toughest beast on the prairie.

Prius will be one of the weakest. It weighs only 2,700 pounds, 500 pounds less than a Camry. How do you sell a car that looks as if it might not stand up to a head-on collision with a grocery cart?

Yet the next generation of American car buyers is maturing fast, and to them, the greenness credentials of Prius might send them to a showroom tomorrow, safety worries or no.

As I stood in the school parking lot with my daughter's science class, the Prius burbling happily beside us, it suddenly shifted from gas to electric. The students were confused at first. Then they "got it."

They clustered around the tailpipe. "Hey, awesome, nothing is coming out," one boy exclaimed. "No smoke, no pollution, no nothing."

I just smiled another Cheshire Cat grin and said, "Exactly."

CAPTION: The view from under the hood of Toyota's new electric/gasoline-powered hybrid Prius.

CAPTION: Toyota President Fujio Cho, right, and Jim Press, executive vice president of Motor Sales USA Inc. with Toyota's Prius at the North American International Auto Show in Detroit.